The semiconductor industry is continuously moving toward the fabrication of smaller and more complex microelectronic components with higher performance. Market pressures are driving the industry to produce smaller components, but there is also significant market pressure to reduce costs while making smaller components. There are numerous steps in the manufacture of many integrated circuits, and each step has an associated cost. Integrated circuits and methods of production that improve quality without requiring significant additional steps can reduce waste and improve reliability.
Many integrated circuits include memory cells to store information, and the memory cells are becoming smaller and more complex along with the rest of the microelectronic components. There are several different types of memory cells, including flash memory that is both non-volatile and re-writable. Non-volatile memory retains stored information even when the memory cell is de-powered, and stored information can be changed when a memory cell is re-writable. Non-volatile memory cells that utilize silicon nanocrystals are included in some integrated circuits, where the memory cells include a memory layer positioned between a select gate and a control gate. The memory layer may include nanocrystals, and the memory cell is read by determining if the nanocrystals have a stored charge or not. The select gate and the control gate are used for reading the memory cell by determining if the nanocrystals have a stored charge, and writing to the memory cell by charging or draining the charge from the memory cell. In some embodiments, the formation process includes a timed etch to form the select gate. The timed etch may not be as accurate or precise as an etch with an end point detection (e.g., an indicator gas that can be detected during the etch), but the relatively small area used for non-volatile memory in some integrated circuits does not produce sufficient indicator gases during the etch to detect the end point of the etch. The timed etch can result in an inaccurate etch that may damage the substrate or leave a coating over the substrate that interferes with operation of the memory cells.
Accordingly, it is desirable to provide methods for producing integrated circuits with a more accurate etch process for forming the select gate, and it is also desirable to provide integrated circuits produced by such methods. In addition, it is desirable to provide methods for detecting the end point of a select gate etch even when the integrated circuit area devoted to the non-volatile memory is low, and integrated circuits produced by such methods. Furthermore, other desirable features and characteristics of the various embodiments will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.